British teenagers Shamima Begum, Amira Abase and Kadiza Sultana walk through a security checkpoint at Gatwick Airport outside London before boarding a flight to Turkey Feb. 17. A U.K. parliamentary committee warned Thursday that other young people could be at risk unless the government takes action to hinder recruitment efforts by the Islamic State group. Reuters

A group of British politicians warned Thursday that an increasing number of U.K. teenagers could be at risk unless the government takes immediate action to prevent them from joining the Islamic State group. The House of Commons Home Affairs Select Committee released a report calling for additional support of families and better messaging to dissuade young people from being lured to Syria and Iraq by online recruiters for the militant group formerly known as either ISIL or ISIS, the Guardian reported.

"We are at the edge of a cliff," committee chairman Keith Vaz said. "The number of cases should ring alarm bells. This must be a relentless battle for hearts and minds -- without a strong counternarrative, we are in danger of more departures."

The parliamentary report came about a month after three teenage girls -- Amira Abase, Shamima Begum and Kadiza Sultana -- went missing in London Feb. 17. The girls flew to Turkey and traveled to Syria, allegedly to join the Islamic State group. Police suspect they were encouraged to skip the country by a friend who had done the same.

Officials have estimated about 600 British nationals have gone to Syria so far, with Vaz telling BBC News that young people were particularly susceptible. "This is grooming of young, vulnerable individuals being preyed upon by extremist groups," he said, adding that schools and police need to work together to prevent children from leaving "even if there is the smallest hint of radicalization."

But Sir Peter Fahy, the chief constable of the Greater Manchester Police and a representative of the Association of Chief Police Officers, told the Business Standard that cops "do not have the capacity" to monitor what's happening at every school in the U.K. The police were criticized for not communicating quickly enough with Turkish authorities after the British girls went missing last month. "The police service will play its part, but the prime responsibility for dissuading young people from getting involved in extremist activity has to lie with parents, families and careers," Fahy said.

The parliamentary committee also recommended that social-media companies should suspend accounts when extremism is suspected, airport check-in desks should increase their scrutiny and the government should create an advice hotline for parents who suspect their kids have been radicalized.